Polyethylene (PE) pipes are widely used in oil and gas transportation, municipal construction. Electrofusion (EF) welding is one of the most commonly used connection method for PE pipes. The welding quality of EF joints is crucial to the safety of PE pipeline. Resistor wire is an important part of pipe fittings, and has great influence in final welding quality and strength of EF joints. In this paper, we discussed the influence of resistor wire for EF fittings in the aspect of selection of resistor wire materials and determination of structural dimensions. Resistivity and temperature coefficient of resistance (TCR) are two factors for material selection. In addition, the influence of resistor wire structure, i.e., resistor wire spacing, resistor wire diameter, on the stress distribution of EF joint was discussed through finite element analysis. The results revealed that the maximum stress in EF joint increase with the diameter of resistor wire, and is barely affected by resistor wire spacing.
Electrofusion (EF) welding is one of the most common connection methods for polyethylene (PE) pipe, as well as thermoplastic pipe and reinforced composite pipe. Conventional EF welding generally adopts constant-voltage welding mode. The welding machine outputs a constant welding voltage to heat the resistance wire within specific welding time. In our previous study, intelligent welding machine was designed to ensure the quality of the EF joint, based on the study of the temperature field in EF joint. In this paper, three experiments were used to show the difference between the intelligent welding machine and traditional welding machine. The intelligent welding machine can actively adjust the welding parameters to ensure the quality of EF joint even it was given the wrong welding voltage and welding time. Compared with the traditional welding machine, the intelligent welding machine can automatically control the maximum temperature and the depth of melting region in EF joint during the welding process, and this method applies for EF joints with various diameters or design welding parameters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.